1. Field of the Invention
The invention relates to a housing for a centrifugal fan, the centrifugal fan, and an electronic device having the centrifugal fan, more particularly to a housing for a centrifugal fan having dust collecting and discharging functionality, the centrifugal fan, and an electronic device having the centrifugal fan.
2. Description of the Related Art
Referring to FIG. 1, in a conventional heat-dissipating module of a notebook computer, a thin type centrifugal fan 1 is generally adopted as a heat-dissipating fan. The centrifugal fan 1 includes a housing 11, and an impeller 12 disposed in the housing 11. The housing 11 defines an accommodation space 111 for accommodating the impeller 12, a plurality of air inlets 112 in fluid communication with the accommodation space 111, and an air outlet 113 in fluid communication with the accommodation space 111. By rotating the impeller 12, air can be drawn into the accommodation space 111 through the air inlets 112 and discharged through the air outlet 113 so as to dissipate the heat around a heat-dissipating fin unit 2 disposed at the air outlet 113.
Since air is laden with dust particles 10 such as fine particles, hair, lint, etc., and since the air outlet 113 of the centrifugal fan 1 is blocked by densely arranged fins 21 of the heat-dissipating fin unit 2, the dust particles 10 are likely to accumulate on a tongue portion 114 of the housing 11, between a hub 121 and vanes 122 of the impeller 12, on sides of the fins 21 of the heat-dissipating fin unit 2 that confront the air outlet 113, and in clearances (not shown) among the fins 21, which may adversely affect the heat-dissipating efficiency of the centrifugal fan 1.
A current dust proofing technology is to isolate the dust particles 10 from a rotary shaft (not shown) of the impeller 12. Although this approach may ensure normal operation of the impeller 12, problems associated with the accumulation of dust particles 10 remain unresolved. Another dust proofing method is to install a dust-proof filter screen on an outer surface of the housing 11 at a position corresponding to the air inlets 112 or on a casing of the notebook computer at a position corresponding to the air inlets 112 so as to prevent the dust particles 10 entrained in the air from entering the accommodation space 111. However, such a design will lead to a reduction in the amount of intake air, which may result in poor heat-dissipating efficiency. Therefore, how to devise a structure that can prevent accumulation of dust particles 10 in the accommodation space 111 of the centrifugal fan 1 without sacrificing the heat-dissipating efficiency of the centrifugal fan 1 is the subject of improvement of the present invention.